Nursing's role during the immediate post myocardial infarction (MI) period includes not only continuous monitoring and assessment but also enforcing coronary precautions, one of which has been the restriction of ice water. Nursing studies do not present conclusive evidence regarding whether this restriction should continue to be enforced, be abandoned, or be modified. The sample size in these studies have been small, randomization procedures have not been apparent, and important factors such as the volume ingested, and the position assumed by the patient, have been inconsistent. Therefore, the purpose of this study is to determine the necessary modifications to the restriction of ice water for patients suffering an MI. A split-plot factorial repeated measures design will structure this study of 100 consenting patients who have suffered an MI. In accordance with the design subjects will be randomly assigned to one of two levels of the nonrepeated factor, i.e., position assumed while ingesting ice water. The sequence in which the subjects will be exposed to the levels of the repeated factor, i.e., volume of ice water, will also be randomly determined. A baseline 12-lead ECG will be obtained prior to ingestion of the designated volume of ice water. Following the ingestion of ice water, 12-lead ECG's will be obtained at the following time intervals: Three minutes, 10 minutes and 25 minutes. The dependent variables will be changes in the T-wave and S-T segment in millimeters summed over all 12 leads. A modification of the analysis of variance will assist in determining the significance of each factor, i.e., position of the patient, volume of ice water, sequence of volume, and time solely and in interaction with each other. Because patients are studied on Days 2 and 3 following admission, there will be those patients who had been suspected of having an MI but in whom this diagnosis was not confirmed. Those patients will be used for comparison purposes. Secondary analysis will address a variety of issues such as the relationship of ECG changes with the location of infarction and peak enzyme values. Additionally the clinical significance of the findings will be determined and prescription for the restriction of ice water will be made.